A branch connector of this type includes an insulating (synthetic resin) housing and a conductive (metal) relay contact supported by the housing. The housing integrally has a first split housing, a second split housing, a connecting portion configured to connect the first split housing and the second split housing to each other in a connectable and separable manner and a locking portion configured to hold a contact state when the first split housing and the second split housing come in contact with each other.
Roughly classified two types of relay contacts have been known. One of them is a type having a groove for insulation displacement that clamps an existing cable (wire) and a crimping terminal that crimps another cable (wire) different from the existing cable (wire) (PTL 1). The other type has a pair of grooves for insulation displacement disposed in parallel. The grooves for insulation displacement clamp the existing cable (wire) and another cable (wire) respectively (PTL 2).
In either type, a relay contact is held in either one of the first split housing and the second split housing. When a cable is connected to the groove for insulation displacement, a cable to be clamped is held while it is placed onto the top (an inlet portion) of a groove for insulation displacement of the relay contact, and in that state, the other split housing is superimposed on (a split housing having) a relay contact and is fitted thereinto. In this manner, a cable coating is cut by the groove for insulation displacement of the relay contact and a core and the relay contact are electrically connected.
On the other hand, in the above described branch connector, there is a growing need for adding a waterproof function. To this need, the branch connector can be configured such that, when the first split housing and the second split housing are brought into contact with each other, a filler such as waterproofing gel or UV curing resin is filled into each split housing. At this time, the filler may be filled into the split housings after it is formed as a separate member.